Manufacture of relief printing forms



April 1937. M. HAGEDORN ET AL 2,078,535

' I MNUFACTURE 0F RELIEF PRINTING FORMS Filed Aug. 16, 1935 In venfors By Affor neyi Patented Apr. 27, 1937 UNITED STATES PATENT OFFICE Max Hagedorn and Gerhard von Kuiawa, Dessau in Anhalt, Germany, alsignors to I. G. Farbenindustrie Aktiengesellschaft,

Frankfort onthe-Main, Germany, a corporation of Germany Application August 18, 1033, Serial No. 885,454 In Germany August 20, 1932 3 Claims.

Our present invention relates to the manufacture of forms for letterpress printing.

One of its objects is a process of manufacturing forms for letterpress printing. Another ob- Ject is the forms for letterpress printing. Further objects will be seen from the detailed speciflcation following hereafter.

It has been proposed, in making relief printing forms, to impress a plastic mass with a relief on a level surface, for instance, a wash-out relief produced on .a chromated gelatin layer or a wash-out relief produced in a non-photographic way. When solidified, the impressedmass represents a negative of the required relief and may, if necessary, be directly used as a relief print- I ing form, after fixing it to a suitable support.

This process, however, could not hitherto obtain practical importance for lack of a suitable plastic material.

According to this invention relief printing forms are made by impressing the relief serving as a pattern either in a dry or slightly wet state,

. into a sheet or foil made of a polymerization product of an unsaturated organic compound, or of a condensation product of such a polymerization product with an aldehyde, a ketone or'the like. Instead of the sheet of foil the unshaped mass of the same product may be used. The product may be a polyacrylic acid derivative (such as an ester, a nitrile or a salt), a polyvinyl halide, a polyvinyl acetate, polystyrol or a mixed polymerization product, for instance, the polymerization product from a mixture of styrol and an acrylic acid ester, from a mixture of a mixture of an acrylic acid ester and acrylic acid nitrile, from a mixture of styrol and a maleic acid ester, or a mlxturefrom vinylmethylether and a methylene malelc acid ester, or a condensation product, for instance, a condensation product from polyvinylalcohol and butyraldehyde or the like. The sheets or foils are prepared in known manner by the pressing process, the spraying processor the celluloid process, or by dissolving the product in an organic solvent and producing the sheet in the, desired thickness by means of a film casting machine. If required the sheet may contain an addition of softening agents, pigments, dyestuffs, filling agents and the like, known in the manufacture of plastic masses. Additions of other highly polymeric substances, such as polyglycols, albuminous substances or cellulose esters, mixed cellulose esters, mixed cel-' lulose ether esters and ethers are also possible.

Sheets made of polyvinyl chloride which contains more than one halogen atom and less than tion:

Example 1.--A gelatin layer applied on a level surface of metal, glass or film, sensitized with potassium bichromate, is exposed under a negative for line and half-tone work and developed into a wash-out relief. -This relief, while on a plane metal plate is brought into a hydraulic press and is pressed while in a dry or slightly wet condition, into a foil made of polyvinyl chloride the chlorine content of which amounts to The foil is also supported one. plane metal plate and the temperature and the pressure of operation are to C. and to atmospheres, respectively. In order that the foil of polyvinyl chloride may be easily detached from the gelatin relief, the latter, prior to pressing, may be treated with a solution of parafiin wax.

Instead of a relief produced from a bichromated gelatin layer, 9. gelatin relief that has been produced in a silver halide emulsion layer by a hardening development may be used. I

Instead of using the polymerization product in the form of a thin foil mounted on a metal, or wooden or similar plate, it may be used in the form of a block which possesses the height necessary for the finished printing block.

Example 2.A gelatin wash-out relief produced as described in Example 1 is impressed in the manner described in that example into a foil made of a mixed polymerization product from vinyl chloride and acrylic acid methylester in the proportion of 3:1 at a pressure of atmospheres and a temperature between 70 and 80 C. the duration of pressure being 5 minutes.

In the single figure of the accompanying drawing there is shown the section of a relief printing form made of polyvinyl chloride containing about 65 per cent of chlorine.

The masses used according to this invention have the advantage that they' can be easily worked inasmuch as they become plastic at a temperature below 120 0.. most of the compounds enumerated can even be worked at a temperature between 70 and 100 C. Furthermore the plastic masses according to this invention can be used again. Thus the costs for the production of relief printing forms are reduced.

What we claim is:

1. A relief printing i'orm comprising the polymerization product of a. vinyl compound.

2. A relief printing form comprising polyvinyl chloride containing about 65 per cent of chlorine.

3. A relief printing form comprising the polymerization product from a mixture of vinyl ch10- ricle and acrylic acid methylester.

MAX HAGEDORN. GERI-IARD v. KUJAWA. 

